The major objective of the proposed research is to determine the efficacy of intermittent extracorporeal hemoglobin carbamylation in the amelioriation of the painful manifestations (crises) and hemolytic anemia of smptomatic patients with S hemoglobin in their erythrocytes. The procedure will be carried out using a machine specifically designed for this purpose (Sicle Cell Machine) by a team headed by A. Babb at the University of Wahington, Seattle. The ultimate goal of the studies is to develop a means of preventing the severe painful manifestations experienced by those sickle patients who manifest the unusually severe form of this disease.